Ball-mill.



No. 833,664. PATENTED OUT. 16, 1906. R. BENEKE.

BALL MILL.

APPLICATION FILED NOV. 4, 1906.

aA/l'nvsss s I I/VVE/V'POB urrnn srarns PATENT OFFICE.

BALL-MILL.

Specification of Letters Patent.

Patented Oct. 16, 1906.

Application filed November 4, 1905. Serial No. $35,907-

To all whom it may concern.-

Be it known that I, liioiiAm Resume, merchant, a subject ol' the King of Prussia, German Emperor, residing at No. 6 Mittelstrasse, Bromberg, German Empire, have invented new and useful Improvements in Ball-Mills, of which the following is a specification.

My inrention fi lates to improvements in ball grinding-mills provided with screens in which the partially-reduced material, still too coarse to pass tlu'ougl'nthc outer sieve, is conducted back to the grinding-drum for further treatment by the balls;

The power required to drive a ball-mill depends, essentially, upon the total weight of the material to be ground and of the grindingballs and on the distance of the center of gravity of this charge from the axis of rotation of the mill. Tl.1e-larger the mill is the greater its capacity and the higher, therefore, the power required to overcome the moment oi inertia due to the elevated charge and which is still further increased by the coarse material traveling back into the drum for further grinding.

The object of my invention is to limit to a minimum the power necessary to drive long mills in which the length of the sieve portion requisite for screening only incloses a relatively short portion of the entire drum or grinding-cylinder; and I attain my object by making the casing or shell for returning the coarse not yet thoroughly connninuted material to the drum of smaller diameter than the outer screen.

One form of construction of my invention is shown in the accompanying drawings, in which Figure 1 is a longitudinal section; Fig. 2, a cross-section on the line 4 4 of Fig 1, and

Fig. 3 a like section 911 the line 5 5 of the,

same figure. The mill-drum 6 is furnished at one end with a trunnion 7, mounted in a plumber-block S and carrying a toothed rim 9 for driving the drum, while at the other end a conical part 10 is provided, the tread-rim 11 of which runs on rollers 1.2. The stationary feed-ho per 14 is fitted in front of the aperture 13 o the cone 10. The material to be ground is fed into the drum 6 through the hopper 14 and is ground during rotation of the drum'by the balls 15. During reduction the material travels toward the opposite end of the drum, where it falls through apertures 16 onto through the screen 18 into the delivery-hopto the grinding-drum.

The moment of power thus resulting is in the new mill considerably decreased by the metal shell 20 being located quite close to the grinding-drum 6, so that only a small space re:

the height of the axial or inclined of the ordinary metal shells.

conducted to the metal shell 20 by collectingchannels 21 of an suitable form. On the inside-wall of the s iell 20 are located the usual axial or inclined guide-walls 22,Which extend almost or quite up to the drum 6,,and, on rotation of the mill conduct the tailings to the ordinary feed device 23, through which the tailings are finally returned to the drum 6 again.

Having thus described my invention, what ters Patent, is I 1. In a ball-mill, in combination, a grinding-drum having perforation in one end of the circumference, screening means surrounding the drum at the perforated end, a returnfeed shell surrounding the remainder of the drum and of smaller diameter than the outer screen, and means for conducting the partlyreduced material from the latter into the reconical screens surrounding it atthe perforated end, a return-feed shell surrounding the remainderof the drum and of smaller discreens 17 18. The fine material passes.

per 19, while the coarser tailings are returned- .In prior mills the path followed by the Paroriginal place of inlet at the hopper end.-

mains between them, whichneed not exceed guide-Walls The tailings sliding from the screen 18 are 2. In a ball-mill, in combination, a terini- I claim as new, and desire to secure by Letturn-feed shell and from this into the grind- I ameter than the outer screen, curved passages my name, this 20th day of October, 1905, in

conducting from the latter into the returnthe presence of two subscribing Witnesses.

feed shell, and means whereby the coarse malterial can pass fgom the said shell into the RICHARD B 5 grinding-drum again, substantially as de- Witnesses: x

scribed. t WOLDEMAR HAUPT,

Inwitness whereof I have hereunto signed HENRY HASPER. 

